Does one always have to present new results when publishing a paper?

I am an undergraduate student who had already worked in two undergrad "research" projects, but both of those projects were basically applications of methods that were already discovered. Furthermore, the results were actually estimations, and not something exact or close. By the end of each one, I had to write a final report for my university, and discussed all the method and results in a poster during a scientific conference of undergrad research in my university.

I had never thought about a possible publication surging from these two projects, but nowadays (it's been two years since the first project) I thought about the fact that I could have published these projects in a formal scientific journal, even though they just confirm an already known method with a certain level of accuracy.

Considering this scenario, my question is that whether it would be possible to publish such kind of research project in form of a formal paper or not, also, would it affect in a positive way my scientific "career", since I would be able to say that I started publishing studies early than the usual (I mean, my knowledge tells me that publish stuff during undergrad means "early")? Moreover, would it be a positive fact to have papers publicized, even if they don't have new results or anything unpublished?